Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pliability”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1980

Improved technique for insertion of intra-aortic balloon pump.

Polytetrafluoroethylene (PTFE, Gortex) grafts have several advantages over woven Dacron grafts for the insertion of intra-aortic balloons (IABP). Because of the smooth inner surface of the PTFE graft, an 8-mm graft may be used instead of the 10-mm minimum size with Dacron. The pliability of the PTFE graft makes it easier to sew with fine suture material, and its comformability permits a "blood tight" seal to be obtained with a single Dacron umbilical tape tie. We have used PTFE grafts for IABP insertion in 24 patients, with no infectious or thrombotic complications. This graft material seems to offer substantial technical advantages over woven Dacron for the insertion of IABP and subsequent arterial repair.

Assisted Circulation↗
PubMed1997

The distally based lateral arm flap for intraoral soft tissue reconstruction.

BACKGROUND: The radial forearm flap is probably the most frequently used among free flaps for intraoral soft tissue reconstruction. However, this flap is not always available. The other fasciocutaneous flaps may be too bulky or less pliable or may have a short vascular pedicle; their use is therefore less than ideal. We present a variant of the lateral arm flap located distally to the lateral epicondyle and having the same advantages as the radial forearm flap. METHODS: Vascular study (dissection and radiography) was previously undertaken to determine the vascular anastomotic network in the epicondylar area, between the posterior radial collateral artery and recurrent arteries running in front of the lateral epicondyle. This demonstrated the possibility of taking a skin paddle on and below the lateral epicondyle, based on the proximal pedicle. RESULTS: We used this flap on three patients for intraoral soft tissue reconstruction (tonsil, floor of the mouth, and piriform sinus). No complication with the flap itself was encountered. In all cases, direct closure of the donor site was possible, with no local complication. CONCLUSION: The distal lateral arm flap (LAF) represents an interesting and reliable alternative to the fasciocutaneous radial forearm flap. The positioning of the skin paddle over the lateral epicondyle and the proximal third of the lateral aspect of the forearm increases pedicle length, thus avoiding the use of vein grafts. Dissection is straightforward with a reliable vascular anatomy. Moreover, in this area, the limited amount of subcutaneous fatty tissue ensures easier placement and more pliability when compared with the standard LAF.

Humans↗
PubMed1998

Aryepiglottic fold: normal topography and clinical implications.

The aryepiglottic folds extend between the arytenoid cartilage and the lateral margin of the epiglottis on each side and constitute the lateral borders of the laryngeal inlet. They are involved in physiologic closure mechanisms of the larynx and in pathologic conditions such as inspiratory stridor. Information on the normal topography of the aryepiglottic folds is poor and controversial. Therefore, this region was reinvestigated in serial whole-organ sections of 25 plastinated normal adult human larynges. Dorsally, the right and the left aryepiglottic folds are separated by the interarytenoid notch and comprise the corniculate and cuneiform cartilages, as well as numerous groups of mucous glands. Ventrally, the aryepiglottic folds are adjacent to the peri-epiglottic adipose tissue. Both regions are clearly separated by several layers of transversely oriented collagenous fiber layers. The muscular constituent of the aryepiglottic folds is only poorly developed, and no muscle fibers insert at the epiglottis. A coherent quadrangular membrane representing a ligamentous "skeleton" of the aryepiglottic folds is absent. A conspicuous collagenous fiber layer is found only to strengthen the free dorsal margin of the fold. Both muscular and ligamentous components may render the aryepiglottic folds sufficiently tense as to resist inspiratory inward suction in normal cases. However, pliability must be preserved to guarantee adequate folding in approximation of the aryepiglottic folds during deglutition. Thereby, the posterior part of the laryngeal inlet is closed, whereas the anterior part is probably closed by independent inward bulging of the peri-epiglottic adipose tissue.

Adult↗
PubMed1981

Plasmodial modifications of erythrocyte surfaces.

The maturation of malarial parasites in red blood cells produces major alterations in the composition and properties of the host cell surfaces. Existing surface-exposed proteins are modified and new antigenic glycoproteins are synthesized by the parasite and inserted into the membrane. Some of the neoproteins are associated with surface excrescences on the host cells and in some cases these foster adhesion of those cells to capillary endothelium. The erythrocyte endoskeleton is degraded and in association the infected cells become deformed and lose pliability. An increase in intracellular Ca2+ may contribute to the changes in host cells surfaces.

Adhesiveness↗
PubMed2003

Workshop in clinical anatomy for residents in gynecology and obstetrics.

A workshop in the clinical anatomy of the female pelvic viscera has been part of the training program for the first year residents in Gynecology and Obstetrics at the University of Padova since the 1999-2000 academic year. The purpose of the workshop is to offer a direct experience of practical anatomy despite a shortage of cadavers. It is designed for six residents who work in three teams on three specimens. The anatomical specimens are unembalmed, unfixed, female pelvic visceral blocs that are harvested from the cadavers 24 hr after death. They are stored at -12 degrees C and removed from the freezer 12 hr before the workshop. The workshop is 3 hr in length and has two parts: one on theory and one practical. In the theoretical section (30 min), the teacher presents the topographical anatomy of the specimens and the residents analyze a clinically oriented worksheet. In the practical section (2 hr), the residents identify viscera, vessels, and nerves through inspection and palpation, and then a step-by-step dissection is carried out. In the last section (30 min), the workshop includes presentations on the three specimens that illustrate anatomical variability and assess knowledge of topographical anatomy. For many residents, this is the first practical experience of the anatomy of the female pelvic viscera because the anatomical courses for medical students do not include direct dissection by students. The unfixed viscera preserves the natural characteristics of the different tissues that exhibit the aspects of living organs, such as color, softness, and pliability, enhancing the knowledge of anatomy. The worksheet is structured as a guide to the anatomical basis of physical examination through inspection and palpation of the viscera. It also introduces the residents to the surgical anatomy of the female pelvis through a brief and selective dissection focused on the relationship between the different regional systems.

Anatomy↗
PubMed2003

Fibronectin anchorage to polymer substrates controls the initial phase of endothelial cell adhesion.

Early stages of the adhesion of human endothelial cells onto a set of smooth polymer films were analyzed to reveal the modulation of cell-matrix interactions by the physicochemical constraints of predeposited fibronectin (FN). Hydrophobic and hydrophilic polymer substrates, consisting of poly(octadecene-alt-maleic anhydride) and poly(propene-alt-maleic anhydride) films, were coated with similar amounts of FN at conditions of either covalent or noncovalent immobilization. The well-defined substrates permit variation of the anchorage of FN at invariant topography, pliability, and molecular composition. Although all of the compared FN coatings were effective in stimulating attachment of endothelial cells, the initial formation of cell-matrix adhesions was found to be controlled by the type of interaction between predeposited FN and the underlying substrate. Covalent linkage and hydrophobic interactions of the predeposited FN with the polymer films interfered with the rapid generation of focal and fibrillar adhesions. It was demonstrated that this was caused by the fact that only weakly bound FN could become readily reorganized by the adherent cells. Upon prolonged culture periods at standard cell culture conditions, secretion and deposition of organized extracellular matrix by the attached cells was found to balance out the differences of the substrates.

Biocompatible Materials↗
PubMed2005

A paradigm for the treatment of prostate cancer bone metastases based on an understanding of tumor cell-microenvironment interactions.

The pliability of cancer cells to mutate into several different phenotypes in an attempt to find one that will survive and colonize at the metastatic site is a tremendous "hurdle" to overcome in designing novel cancer therapeutics. New targets of therapy are essential if we are to effectively overcome the evasiveness of cancer. The interaction between the tumor cell and the surrounding microenvironment creates a vicious cycle that perpetuates disease survival and progression. The future of cancer therapy resides in the ability to focus on the recruited and exploited relationships of the cancer cell with the host environment. These therapies target cancer cell growth early and interrupt the vicious cycle that is created by the tumor cells interacting with bone components by inhibiting osteoclasts, osteoblasts, stromal cells, and endothelial cells. They alter the bone microenvironment, creating a hostile "soil" that prevents the "seed" from developing into bone metastases and represent a potential new platform for the development of prostate cancer therapeutics.

Bone Neoplasms↗
PubMed2005

Treatment of hypertrophic scars and keloids with a radiofrequency device: a study of collagen effects.

BACKGROUND AND OBJECTIVE: To determine the efficacy and safety of the ThermaCool TC radiofrequency system for treatment of hypertrophic and keloid scars and evaluate treatment associated collagen changes. MATERIALS AND METHODS: Six subjects with hypertrophic and four with keloid scars were treated with the ThermaCool device: one-third of the scar received no treatment (control), one-third received one treatment and one-third received two treatments (4-week interval). Scars were graded before and then 12 and 24 weeks after treatment on symptoms, pigmentation, vascularity, pliability, and height. Biopsies were taken from four subjects with hypertrophic scars and evaluated with hematoxylin and eosin (H & E) staining, multiphoton microscopy, and pro-collagen I and III immunohistochemistry. RESULTS: No adverse treatment effects occurred. Clinical and H & E evaluation revealed no significant differences between control and treatment sites. Differences in collagen morphology were detected in some subjects. Increased collagen production (type III > type I) was observed, appeared to peak between 6 and 10 weeks post-treatment and had not returned to baseline even after 12 weeks. CONCLUSION: Use of the thermage radiofrequency device on hypertrophic scars resulted in collagen fibril morphology and production changes. ThermaCool alone did not achieve clinical hypertrophic scar or keloid improvement. The collagen effects of this device should be evaluated further in order to optimize its therapeutic potential for all indications.

Adult↗
PubMed2003

Construction of molecular assemblies via docking: modeling of tetramers with D2 symmetry.

Comparative modeling methods are commonly used to construct models of homologous proteins or oligomers. However, comparative modeling may be inapplicable when the number of subunits in a modeled oligomer is different than in the modeling template. Thus, a dimer cannot be a template for a tetramer because a new monomer-monomer interface must be predicted. We present in this study a new prediction approach, which combines protein-protein docking with either of two tetramer-forming algorithms designed to predict the structures of tetramers with D2 symmetry. Both algorithms impose symmetry constraints. However, one of them requires identification of two of the C2 dimers within the tetramer in the docking step, whereas the other, less demanding algorithm, requires identification of only one such dimer. Starting from the structure of one subunit, the procedures successfully reconstructed 16 known D2 tetramers, which crystallize with either a monomer, a dimer or a tetramer in the asymmetric unit. In some cases we obtained clusters of native-like tetramers that differ in the relative rotation of the two identical dimers within the tetramer. The predicted structural pliability for concanavalin-A, phosphofructokinase, and fructose-1,6-bisphosphatase agrees semiquantitatively with the observed differences between the several experimental structures of these tetramers. Hence, our procedure identifies a structural soft-mode that allows regulation via relative rigid-body movements of the dimers within these tetramers. The algorithm also predicted three nearly correct tetramers from model structures of single subunits, which were constructed by comparative modeling from subunits of homologous tetrameric, dimeric, or hexameric systems.

Algorithms↗
PubMed1986

Polarized light microscopy in the study of the molecular structure of collagen and reticulin.

Although collagen structure has been studied by polarized light microscopy since the early 19th century and continued since, modern studies and reviews failed to correlate the conclusions based on data obtained by the techniques with those of polarized light microscopy. Collagen I is intensely positively birefringent in respect to length of the fibres; the positive intrinsic birefringence indicates a quasi-crystalline alignment parallel to the fibre and molecule axis of the amino acid residues of the polypeptide chains. This would not have been compatible with a helical structure but has been achieved by similar tilt angles and opposite directions of the coiling and supercoiling. Birefringence characteristics of collagen are also affected by chemical treatments, extractions and staining procedures. Attachment of chemical groups to the anionic charges present on the surface of collagen molecules results in increased positive birefringence in the case of bipolar molecules attached to two or more anionic residues. Unipolar attachment to the same groups, or to the cationic groups of the associated proteoglycans, as well as sulfation or acetylation of hydroxyls of the protein and/or the carbohydrate, reduced or reversed the sign of birefringence. Increased birefringence caused by stretching cannot be due to intramolecular events and is caused by intermolecular changes. The same applies to changes in collagen during aging. Reticulin is a group of different substances which mostly contain collagen III. The pliability and deformability of this collagen is related to its weakly negative birefringence due to large side chains and presence of different and greater amounts of interstitial proteoglycans and other molecules. The so-called reticulin of healing wounds differs in its constitution from other reticulins but is also rich in intermolecular carbohydrate components.

Birefringence↗
PubMed1983

Pathogenesis of the "Courvoisier gallbladder".

To investigate the pathophysiological basis of Courvoisier's law, the gallbladder size and pliability were measured in chronic calculous cholecystitis with (7 patients) or without (25 patients) common duct obstruction, in periampullary malignancy (6 patients), and in the normal state (3 patients). The duration and level of jaundice, when present, were correlated to the gallbladder size and ductal pressure as measured at operation. It was found that in vitro the gallbladders were equally pliable in all groups. Therefore, the classical explanation, that stone obstruction of the common duct does not result in dilated gallbladders because of less pliable organs from preexisting fibrosis, does not seem to apply for this series of patients. A markedly higher ductal pressure and a longer history of and deeper jaundice were also found in patients with dilated gallbladders. The data of this study support the alternative explanation that chronically increased ductal pressure is the probable cause of dilated gallbladders seen in malignant obstruction of the common duct.

Ampulla of Vater↗
PubMed2003

Evolution of birds: ichthyosaur integumental fibers conform to dromaeosaur protofeathers.

Filamentous integumentary structures have been reported as protofeathers in dromaeosaurs (non-avian dinosaurs). This hypothesis is considered against data on the complex architecture of dermal and subdermal collagenous fibers widely prevalent in living and extinct animals. Ichthyosaur integumental fibers, as dromaeosaur "protofeathers", are the most external structures preserved. Marked similarities are shown in branching patterns of these fibers compared with those of the dromaeosaur Sinornithosaurus; hence distinguishing between aberrant and primary features is difficult. Analysis of a pterosaur specimen shows that bent and straight fibers on the wings have functional implications. The fibers conform to the twofold shape of collagen and contradict the notion that bent integumental structures in the dinosaur Sinosauropteryx indicate softness and pliability. A suggestion also concerning Sinosauropteryx is that integumental structures with darker edges, compared with the middle, imply that they were hollow. Investigation of a similar condition in an ichthyosaur shows that it is more likely a consequence of mineralization. Dermal collagen fibers in, for example, sharks, dolphins, snakes, and turtles are shown to be grouped in bundles of varying sizes. Degradation of the dermis results in the breakdown of the fiber bundles and formation of myriad patterns of the disrupted fibers, as noted in decomposed dolphin skin. The overall findings of the study are that the thesis of dinosaur "protofeathers" requires more substantial support than exists at present.

Animals↗
PubMed2005

Design and features of the Acorn CorCap Cardiac Support Device: the concept of passive mechanical diastolic support.

The Laplace equation points to the importance of ventricular wall stress as a factor in heart failure development and progression. Based on animal and clinical experience with active and passive cardiomyoplasty, a synthetic passive constraint was proposed as a means of reducing excessive wall stress, and thus assuaging disease progression. The Acorn CorCap CSD Cardiac Support Device was designed to provide passive diastolic support and serve as a constraint against chronic cardiac dilation in heart failure. Basic and uncomplicated in appearance, the device nevertheless incorporates numerous sophisticated structural and functional features intended maximize therapeutic value. The device is fabricated from medical grade multifilament polyester yarn, in a specific knit construction chosen to provide structural integrity, low physical profile, pliability for intimate contact with the epicardial surface, ease of manipulation during implantation, and anisotropic compliance characteristics to encourage beneficial reverse remodeling.

Cardiomyopathy, Dilated↗
PubMed1982

Platysma musculocutaneous flap: clinical and anatomic considerations in head and neck reconstruction.

The platysma musculocutaneous flap was used in 14 patients for reconstruction of the oral lining and external skin coverage in the head and neck area. Complications occurred in five patients. Only one patient, however, required further surgery and this was for correction of a poor cosmetic result. The skin and subjacent muscle are supplied by a major vascular pedicle from the facial artery and vein and a minor pedicle from the transverse cervical artery and vein. Either pedicle can be used as the pivot for the flap's arc of rotation. The donor defect can be closed primarily and did not present any problems. The flap can be raised with both its motor and sensory supply intact. The thinness and pliability, color match, and proximity make this flap a useful adjunct in head and neck surgery.

Aged↗
PubMed1996

Pathologic aspects of polytetrafluoroethylene sutures in human heart.

BACKGROUND: Polytetrafluoroethylene (PTFE) sutures have been widely used as a mitral chord substitute. We present the cases of 4 patients who underwent mitral valve repair with chordal replacement by PTFE sutures and these required another operation. This gave us the chance to examine the PTFE sutures. METHODS: Structural analysis of the PTFE sutures was performed 26 to 378 days postoperatively. The specimens were examined grossly, microscopically, and by scanning or transmission electron microscopy or both. RESULTS: The PTFE suture in 1 patient was found to be completely covered with endothelial cells 154 days postoperatively. There was no calcification, and the flexibility and pliability of the PTFE sutures was preserved. Even though the PTFE sutures seemed uncovered on visual inspection, there was a thin lining of collagen and fibrin on the surface. Endothelial cells were seen in areas that looked clear in one specimen 26 days postoperatively. CONCLUSIONS: We think that the new layer of collagen could be promising in terms of durability and that the endothelial layer wil resemble normal tissue in its anticoagulant properties.

Female↗
PubMed1991

Vertical dimension: a dynamic concept based on facial form and oropharyngeal function.

Craniofacial vertical dimension is a more accurate measure of facial proportion than mere measurement of the mid and lower part of the face. Craniomaxillary dimension is skeletally determined, whereas facial height of the lower part of the face is partly dependent on the vertical dimension of occlusion. Alterations in the vertical dimension of occlusion can dramatically affect the esthetics of the soft facial tissue. The "Golden Proportion" quantitatively defines ideal measured relationships and encourages a scientific appreciation of beauty. Faces with deficiencies in lower facial balance (brachyfacial) often exhibit insufficient height of the occlusal plane. The scientific literature has suggested a pliability of skeletal muscle allowing for physiologic variance in vertical facial height. Temporomandibular joint compliance is demonstrated with elevations in resting muscle length. Facial balance and location of the occlusal planes are the primary determinants for establishing an appropriate vertical dimension of occlusion.

Electromyography↗
PubMed1989

Efficacy of aortic balloon valvoplasty: direct measurement of orificial area in a model with pulsatile flow.

The efficacy of balloon valvoplasty of calcific aortic stenosis remains controversial. We studied, therefore, 5 human aortic valves obtained at necropsy in a positive-displacement pulse duplicator which delivered stroke volumes of 40-100 ml with a quasiphysiological waveform of flow. All valves had three leaflets without commissural fusion and were preserved in antibiotic solution before study. Orificial area was planimetered from videotape of opening of the valve and varied with flow in all cases. Valvoplasty with a 20 mm diameter balloon had no effect on the orifice of the normal valve but increased the orifice of 2 mildly calcified valves from 0.70-1.77 cm2 (range) at baseline to 1.06-1.95 cm2. In 2 valves with severe calcification of the leaflets, the orifice was increased from 0.31-0.82 cm2 to 0.73-1.07 cm2. Dual balloon valvoplasty achieved a variable but small further increase in orificial area. No valve showed tears of the leaflets or fracture of calcific deposits after valvoplasty. We conclude that balloon valvoplasty can acutely increase orificial area, independently of any change in stroke volume. In valves without commissural fusion, its mechanism appears to be an increase in the pliability of the leaflets which does not require macroscopic fracture of calcific deposits.

Adult↗
PubMed1991

The vascularized fibula graft in mandibular reconstruction.

The use of a vascularized graft from the fibula for mandibular reconstruction is presented. The great strength, pliability, and long vascular pedicle that characterize such grafts make them particularly suitable for this type of repair. The results in six cases were highly satisfactory. Masticatory function was well restored, without alteration of the facial contour, and with minimal sequelae at the donor site.

Adult↗